iOS －－制作画板 －－2

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>//一定导入UIKit框架
@interface PathModel : NSObject

@property(nonatomic,assign)CGMutablePathRef path;//路径（需要调用set方法retain）
@property(nonatomic,strong)UIColor *color;//颜色
@property(nonatomic,assign)CGFloat lineWidth;//线宽

@end

//记得要将路径计数值加一，复写set方法
#import "PathModel.h"

@implementation PathModel

-(void)dealloc
{
CGPathRelease(_path);
}

- (void)setPath:(CGMutablePathRef)path
{
//使路径的计数值加一，这样在DrawView中释放路径后，model中仍然存在，不会出现野指针
CGPathRetain(path);
_path = path;
}
@end

#import "DrawView.h"
#import "PathModel.h"
@implementation DrawView

-(instancetype)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self)
{
//设置默认值
_lineWidth = 1;
_color = [UIColor blackColor];

}
return self;
}

- (void)drawRect:(CGRect)rect {

//如果可变数组不是空的，则需要重新绘制之前的路径
if (_pathArray.count>0)
{
for (int i = 0; i<_pathArray.count; i++)
{
//遍历数组中的所有元素 取出model中的属性并绘制之前的线条
PathModel *model = _pathArray[i];
CGContextRef context = UIGraphicsGetCurrentContext();
CGMutablePathRef path = model.path;
UIColor *color = model.color;
CGFloat width = model.lineWidth;
//绘制
CGContextAddPath(context, path);
//设置填充颜色
[color set];
//设置线宽
CGContextSetLineWidth(context, width);

//设置头尾及连接点的类型为圆的，
CGContextSetLineJoin(context, kCGLineJoinRound);
CGContextSetLineCap(context, kCGLineCapRound);
CGContextDrawPath(context, kCGPathStroke);
}
}
//当_LinePath不为空的时候，说明开始绘制新的线条，颜色和线宽就是在视图控制器中通过block块传递过来的参数
if (_LinePath != nil)
{
CGContextRef context = UIGraphicsGetCurrentContext();

[_color set];
CGContextSetLineWidth(context, _lineWidth);

CGContextAddPath(context, _LinePath);

CGContextDrawPath(context, kCGPathStroke);
}

}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
//取得手指开始触摸的点的坐标
CGPoint p = [[touches anyObject] locationInView:self];
//创建路径
_LinePath  = CGPathCreateMutable();
//获得路径开始的点的坐标
CGPathMoveToPoint(_LinePath, NULL, p.x, p.y);
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
//获得手指一动过程中经过的点的坐标
CGPoint p = [[touches anyObject]locationInView:self];
//将这些点添加到路径中
CGPathAddLineToPoint(_LinePath, NULL, p.x,p.y);
//重新绘制
[self setNeedsDisplay];
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
//创建一个可变数组，存放model对象，（model中有颜色，线宽，路径三个属性）
if (_pathArray==nil)
{
_pathArray = [[NSMutableArray alloc]init];

}
//创建model对象，并且给model中的属性赋值
PathModel *model = [[PathModel alloc]init];
model.path = _LinePath;
model.lineWidth = _lineWidth;
model.color = _color;
//将model存放到可变数组中
[_pathArray addObject:model];
//手指结束触摸时将路径释放掉
CGPathRelease(_LinePath);
_LinePath = nil;

}

- (void)undo
{
if (_pathArray.count>0)
{
[_pathArray removeLastObject];
[self setNeedsDisplay];
}
}
- (void)clear
{
if (_pathArray.count>0)
{
[_pathArray removeAllObjects];
[self setNeedsDisplay];
}
}

@end